Method of manufacturing display unit using laser removal of organic material

ABSTRACT

A laminated structure is formed by placing a cover substrate over a device substrate with a projection structure in between in the vacuum atmosphere. Next, the laminated structure is taken out into the air in a state that a space between the device substrate and the cover substrate is maintained in the vacuum atmosphere. Subsequently, the portion of the organic layer formed on the auxiliary electrode is removed by irradiating laser light to the laminated structure. Since the space between the device substrate and the cover substrate is maintained in the vacuum atmosphere, even if the laser light is emitted to the laminated structure taken out into the air, the laser light is emitted to the portion of the organic layer formed on the auxiliary electrode in the vacuum atmosphere.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese PatentApplication JP 2007-132824 filed in the Japanese Patent Office on May18, 2007, the entire contents of which being incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing a displayunit including an organic light emitting device.

2. Description of the Related Art

As such a kind of display unit, for example, as shown in FIG. 21, adisplay unit in which a first electrode 813 is formed on a substrate 811for every organic light emitting device, and thereon an organic layer816 including a light emitting layer and a second electrode 817 aresequentially layered is known. Since the second electrode 817 is a thinfilm common electrode, the resistance value is high, and the voltagedrop is different according to each distance from a power source (notshown) to each organic light emitting device. Thereby, luminancevariation may be generated in the screen. To inhibit such luminancevariation, in some cases, a relatively thick auxiliary electrode 814 isprovided in a region between each first electrode 813, and the auxiliaryelectrode 814 and the second electrode 817 are electrically connected.

To electrically connect the second electrode 817 to the auxiliaryelectrode 814, it is necessary to remove a portion of the organic layer816 formed on the auxiliary electrode 814 before forming the secondelectrode 817. In some cases, the organic layer 816 is formed only onthe first electrode 813 by using a mask or the like. In other cases, theorganic layer 816 is formed on almost the whole area of the displayregion of the substrate 810. In any cases, there is a possibility thatthe auxiliary electrode 814 is covered with the organic layer 816.

In the past, for example, Japanese Unexamined Patent ApplicationPublication No. 2005-11810 describes that it is desirable to remove theportion of the organic layer formed on the auxiliary electrode by laserirradiation in a chamber maintained under reduced pressure.

SUMMARY OF THE INVENTION

However, in Japanese Unexamined Patent Application Publication No.2005-11810, there is no description for a method of maintaining thevacuum atmosphere.

In general, as a method of irradiating laser light in a vacuum chamber,the following methods are possibly used. In one of the methods, anairtight opening (glass window) for transmitting laser light is arrangedin the vacuum chamber, and the laser light is emitted from outside ofthe chamber. In another method, a laser light source and an operatingsection thereof are arranged in the chamber, and thereby laser light isemitted. However, in the foregoing methods, when a large substrate isused as a substrate on which the organic light emitting device isprovided, the glass window of the vacuum chamber is jumboized andtherefore it has been difficult to realize such arrangement in terms ofequipment. Further, in the foregoing methods, the configuration of thevacuum chamber, the laser light source, and the operating sectionthereof are complicated and grows in size, and the increased equipmentcost has been an issue.

As described above, in the past, a method of removing the portion of theorganic layer formed on the auxiliary electrode by laser irradiation inthe vacuum atmosphere has not been yet developed.

In view of the foregoing, in the invention, it is desirable to provide amethod of manufacturing a display unit capable of removing the portionof the organic layer formed on the auxiliary electrode by laserirradiation in the vacuum atmosphere.

According to an embodiment of the invention, there is provided a methodof manufacturing a display unit having a plurality of organic lightemitting devices on a substrate. The method of manufacturing a displayunit includes the steps of: forming a plurality of first electrodes, anauxiliary electrode in a region between the plurality of firstelectrodes, a projection structure made of an insulating material in aregion between the plurality of first electrodes and the auxiliaryelectrode, and an organic layer covering the plurality of firstelectrodes and the auxiliary electrode over the substrate, and therebyforming a device substrate; selectively removing a portion of theorganic layer formed on the auxiliary electrode; and forming a secondelectrode on the organic layer and the auxiliary electrode. The step ofselectively removing the portion of the organic layer formed on theauxiliary electrode includes the following steps A to C:

A: a step of forming a laminated structure by placing a cover substrateover device substrate with the projection structure in between in thevacuum atmosphere,

B: a step of taking out the laminated structure into the air in a statethat at least a space between the cover substrate and the portion of theorganic layer formed on the auxiliary electrode is maintained in thevacuum atmosphere, and

C: a step of irradiating laser light to the laminated structure.

In the method of manufacturing a display unit according to theembodiment of the invention, the projection structure has a function asa spacer between the device substrate and the cover substrate.Therefore, even in the state that the device substrate is laminated overthe cover substrate, the space is generated between the device substrateand the cover substrate. The space may be maintained in the vacuumatmosphere even if the laminated structure is taken out into the air.Even if the laser light is emitted to the laminated structure taken outinto the air, the laser light is emitted to the portion of the organiclayer formed on the auxiliary electrode in the vacuum atmosphere.

According to the method of manufacturing a display unit of theembodiment of the invention, in the step of selectively removing theportion of the organic layer formed on the auxiliary electrode, thedevice substrate is laminated over the cover substrate with theprojection structure in between in the vacuum atmosphere and thereby thelaminated structure is formed; the laminated structure is taken out intothe air in the state that at least the space between the cover substrateand the portion of the organic layer formed on the auxiliary electrodeis maintained in the vacuum atmosphere; and then the laser light isemitted to the laminated structure. Therefore, the portion of theorganic layer formed on the auxiliary electrode may be removed by laserirradiation in the vacuum atmosphere.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a configuration of a display unit accordingto an embodiment of the invention;

FIG. 2 is a diagram showing an example of the pixel driving circuitshown in FIG. 1;

FIG. 3 is a plan view showing a structure of the display region shown inFIG. 1;

FIG. 4 is a cross section showing a structure of the organic lightemitting device shown in FIG. 3;

FIG. 5 is a plan view showing another structure of the display regionshown in FIG. 3;

FIG. 6 is a plan view showing still another structure of the displayregion shown in FIG. 3;

FIG. 7 is a cross section showing a method of manufacturing the displayunit shown in FIG. 1 in the order of steps;

FIGS. 8A and 8B are views for explaining an example of a step followingFIG. 7;

FIGS. 9A and 9B are views for explaining another example of a stepfollowing FIG. 7;

FIGS. 10A and 10B are views for explaining a step following FIGS. 8A,8B, 9A, and 9B;

FIG. 11 is a view for explaining another example of the step shown inFIG. 10A;

FIGS. 12A and 12B are views for explaining a step following FIGS. 10A,10B, and 11;

FIG. 13 is a cross section showing another structure of the organiclight emitting device shown in FIG. 1;

FIG. 14 is a cross section showing still another structure of theorganic light emitting device shown in FIG. 1;

FIG. 15 is a plan view showing a schematic structure of a moduleincluding the display unit of the foregoing embodiment;

FIG. 16 is a perspective view showing an appearance of a firstapplication example of the display unit of the foregoing embodiment;

FIG. 17A is a perspective view showing an appearance viewed from thefront side of a second application example, and FIG. 17B is aperspective view showing an appearance viewed from the rear side of thesecond application example;

FIG. 18 is a perspective view showing an appearance of a thirdapplication example;

FIG. 19 is a perspective view showing an appearance of a fourthapplication example;

FIG. 20A is an elevation view of a fifth application example unclosed,FIG. 20B is a side view thereof, FIG. 20C is an elevation view of thefifth application example closed, FIG. 20D is a left side view thereof,FIG. 20E is a right side view thereof, FIG. 20F is a top view thereof,and FIG. 20G is a bottom view thereof; and

FIG. 21 is a plan view showing a configuration of a display unit of therelated art having an organic light emitting device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the invention will be hereinafter described in detailwith reference to the drawings.

FIG. 1 shows a configuration of a display unit according to anembodiment of the invention. The display unit is used as an ultrathinorganic light emitting color display unit or the like. In the displayunit, for example, a display region 110 in which a plurality of organiclight emitting devices 10R, 10G, and 10B described later are arranged ina matrix state is formed on a substrate 11 made of glass. A signal linedriving circuit 120 and a scanning line driving circuit 130 that aredrivers for displaying an image are formed on the periphery of thedisplay region 110.

In the display region 110, a pixel driving circuit 140 is formed. FIG. 2shows an example of the pixel driving circuit 140. The pixel drivingcircuit 140 is formed in a layer under a first electrode 13 describedlater. The pixel driving circuit 140 is an active driving circuit havinga driving transistor Tr1, a writing transistor Tr2, a capacitor(retention volume) Cs between the driving transistor Tr1 and the writingtransistor Tr2, and the organic light emitting device 10R (or 10G, 10B)serially connected to the driving transistor Tr1 between a first powerline (Vcc) and a second power line (GND). The driving transistor Tr1 andthe writing transistor Tr2 are composed of a general thin filmtransistor (TFT (Thin Film Transistor)). The structure thereof is notparticularly limited, and may be, for example, inversely staggeredstructure (so-called bottom gate type) or staggered structure (top gatetype).

In the pixel driving circuit 140, a plurality of signal lines 120A arearranged in the column direction, and a plurality of scanning lines 130Aare arranged in the row direction. Each intersect between each signalline 120A and each scanning line 130A corresponds to one of the organiclight emitting devices 10R, 10G, and 10B (sub pixel). Each signal line120A is connected to the signal line driving circuit 120. An imagesignal is supplied to a source electrode of the writing transistor Tr2from the signal line driving circuit 120 through the signal line 120A.Each scanning line 130A is connected to the scanning line drivingcircuit 130. A scanning signal is sequentially supplied to a gateelectrode of the writing transistor Tr2 from the scanning line drivingcircuit 130 through the scanning line 130A.

FIG. 3 shows an example of a planar structure of the display region 110.In the display region 110, the organic light emitting device 10Rgenerating red light, the organic light emitting device 10G generatinggreen light, and the organic light emitting device 10B generating bluelight are sequentially provided in a matrix state as a whole. Theorganic light emitting devices 10R, 10G, and 10B have reed-shaped planarshape, and a combination of the organic light emitting devices 10R, 10G,and 10B adjacent to each other composes one pixel.

FIG. 4 shows a cross sectional structure of the organic light emittingdevices 10R, 10G, and 10B shown in FIG. 3. In the organic light emittingdevices 10R, 10G, and 10B, the foregoing driving transistor Tr1 of thepixel driving circuit 140, a planarizing insulating film 12, the firstelectrode 13 as an anode, an auxiliary electrode 14, a projectionstructure 15 made of an insulating material, an organic layer 16including a light emitting layer described later, and a second electrode17 as a cathode are layered in this order from the substrate 11 side.

The organic light emitting devices 10R, 10G, and 10B as above are coatedwith a protective film (not shown) made of silicon nitride (SiN),silicon oxide (SiO) or the like according to need. Further, a sealingsubstrate (not shown) made of glass or the like is bonded to over thewhole area of the protective film with an adhesive layer (not shown)made of a thermoset resin, an ultraviolet cure resin or the like inbetween, and thereby the organic light emitting devices 10R, 10G, and10B are sealed.

The driving transistor Tr1 is electrically connected to the firstelectrode 13 through a connection hole 12A provided in the planarizinginsulating film 12.

The planarizing insulating film 12 is intended to planarize a front faceof the substrate 11 formed with the pixel driving circuit 140. Since thefine connection hole 12A is formed in the planarizing insulating film12, the planarizing insulating film 12 is preferably made of a materialhaving favorable pattern precision. As a material of the planarizinginsulating film 12, for example, an organic material such as polyimide,an inorganic material such as silicon oxide (SiO₂) or the like is cited.

The first electrode 13 is formed correspondingly to the respectiveorganic light emitting devices 10R, 10G, and 10B. Further, the firstelectrode 13 has a function as a reflecting electrode to reflect lightgenerated in the light emitting layer, and desirably has highreflectance as much as possible in order to improve light emittingefficiency. The first electrode 13 is, for example, from 100 nm to 1000nm thick, and is made of a simple substance or an alloy of metalelements such as silver (Ag), aluminum (Al), chromium (Cr), titanium(Ti), iron (Fe), cobalt (Co), nickel (Ni), molybdenum (Mo), copper (Cu),tantalum (Ta), tungsten (W), platinum (Pt), and gold (Au).

The auxiliary electrode 14 is intended to prevent large difference involtage drop according to the distance from a power source (not shown)to the respective organic light emitting devices 10R, 10G, and 10B andthereby inhibit in-plane luminance variation. The auxiliary electrode 14is formed in a region between each first electrode 13. Further, theauxiliary electrode 14 is electrically insulated from the firstelectrode 13 by the projection structure 15, and is electricallyconnected to the second electrode 17. That is, the top face of theauxiliary electrode 14 is not covered with the organic layer 16, andsuch an exposed portion is a contact region with the second electrode17. It is desirable that the entire top face of the auxiliary electrode14 is electrically connected to the second electrode 17. However, atleast part of the top face of the auxiliary electrode 14 may beelectrically connected to the second electrode 17.

The auxiliary electrode 14 is made of, for example, a simple substanceor an alloy of metal elements such as silver (Ag), aluminum (Al),chromium (Cr), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni),molybdenum (Mo), copper (Cu), tantalum (Ta), tungsten (W), platinum(Pt), and gold (Au). The auxiliary electrode 14 may be made of the samematerial as that of the first electrode 13, or may be made of adifferent material. Further, the auxiliary electrode 14 is desirablymade of a material having high absorbency to the after-mentioned laserlight.

The projection structure 15 is formed in a region between the firstelectrode 13 and the auxiliary electrode 14. The projection structure 15has a function as an interelectrode insulating film to secure insulationproperties between the first electrode 13 and the auxiliary electrode14/the second electrode 17 and to accurately obtain a desired shape ofthe light emitting region. The projection structure 15 is made of, forexample, an organic material such as polyimide or an inorganicinsulating material such as oxide silicon (SiO₂), and has an openingcorrespondingly to the light emitting region of the first electrode 13and the auxiliary electrode 14. The organic layer 16 and the secondelectrode 17 may be sequentially provided on the projection structure 15as well in addition to the light emitting region. However, lightemission is generated only in the opening of the projection structure 15corresponding to the first electrode 13.

The projection structure 15 also has a function to secure space Sbetween a cover substrate 61 and a portion of the organic layer 16formed on the auxiliary electrode 14 as a spacer to the cover substrate61 when the portion of the organic layer 16 formed on the auxiliaryelectrode 14 is selectively removed in the after-mentioned manufacturingstep. To that end, height H of the projection structure 15 ispreferably, for example, 2 μm or more from the front face of the firstelectrode 13 and the front face of the auxiliary electrode 14.

The projection structure 15 has a two-stage structure composed of a base15A provided in a region between the first electrode 13 and theauxiliary electrode 14 and a rib 15B provided on the top face of thebase 15A. The rib 15B enables to reduce the contact area between theprojection structure 15 and the cover substrate 61 in theafter-mentioned manufacturing step. Thus, the cover substrate 61 isstably laminated over the projection structure 15 with no gap betweenthe projection structure 15 and the cover substrate 61. The rib 15B isformed over the whole area of the display region 110. The rib 15B may beformed uniformly on the top face of the base 15A (refer to FIG. 6).Otherwise, the rib 15B may be formed independently on part of the topface of the base 15A (refer to FIG. 3 and FIG. 5). The latter caseincludes a case in which the rib 15B is provided along the long side ofthe first electrode 13 as shown in FIG. 3 and a case in which the rib15B is provided along the short side of the first electrode 13 as shownin FIG. 5. The former case includes a case in which the rib 15B issequentially provided along the four sides of the first electrode 13 asshown in FIG. 6.

The organic layer 16 has, for example, a structure in which a holeinjection layer, a hole transport layer, the light emitting layer, andan electron transport layer (all elements are not shown) aresequentially layered from the first electrode 13 side. Of the foregoinglayers, the layers other than the light emitting layer may be providedaccording to need. Further, the organic layer 16 may have a structuredifferent according to the light emitting color of the organic lightemitting devices 10R, 10G, and 10B. The hole injection layer is intendedto improve the hole injection efficiency and functions as a buffer layerto prevent leakage. The hole transport layer is intended to improveefficiency to transport a hole to the light emitting layer. The lightemitting layer is intended to generate light due to electron-holerecombination by applying the electric field. The electron transportlayer is intended to improve efficiency to transport electrons to thelight emitting layer.

Materials for the hole injection layer of the organic light emittingdevice 10R include, for example, 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA) or 4,4′,4″-tris(2-naphthylphenylamino)triphenylamine (2-TNATA). Materials forthe hole transport layer of the organic light emitting device 10Rinclude, for example, bis[(N-naphthyl)-N-phenyl]benzidine (α-NPD).Materials for the light emitting layer of the organic light emittingdevice 10R include, for example, a material in which 30 wt % of2,6≡bis[4′≡-methoxydiphenylamino)styryl]≡1,5≡dicyanonaphthalene (BSN) ismixed with 9,10-di-(2-naphthyl)anthracene (ADN). Materials for theelectron transport layer of the organic light emitting device 10Rinclude, for example, 8-hydroxyquinoline aluminum (Alq₃).

Materials for the hole injection layer of the organic light emittingdevice 10G include, for example, m-MTDATA or 2-TNATA. Materials for thehole transport layer of the organic light emitting device 10G include,for example, α-NPD. Materials for the light emitting layer of theorganic light emitting device 10G include, for example, a material inwhich 5 volume % of coumarin 6 is mixed with ADN. Materials for theelectron transport layer of the organic light emitting device 10Ginclude, for example, Alq₃.

Materials for the hole injection layer of the organic light emittingdevice 10B include, for example, m-MTDATA or 2-TNATA. Materials for thehole transport layer of the organic light emitting device 10B include,for example, α-NPD. Materials for the light emitting layer of theorganic light emitting device 10B include, for example, a material inwhich 2.5 wt % of 4,4′≡bis[2≡{4≡(N,N≡diphenylamino)phenyl}vinyl]biphenyl(DPAVBi) is mixed with ADN. Materials for the electron transport layerof the organic light emitting device 10B include, for example, Alq₃.

The second electrode 17 is, for example, from 5 nm to 50 nm thick, andis made of a simple substance or an alloy of metal elements such asaluminum (Al), magnesium (Mg), calcium (Ca), and sodium (Na). Specially,an alloy of magnesium and silver (MgAg alloy) or an alloy of aluminum(Al) and lithium (Li) (AlLi alloy) is preferable. Further, the secondelectrode 17 may be made of ITO (indium tin composite oxide) or IZO(indium zinc composite oxide).

The display unit is manufactured, for example, as follows.

FIG. 7 to FIG. 12B show a method of manufacturing the display unit inthe order of steps. First, as shown in FIG. 7, the substrate 11 made ofthe foregoing material is prepared, and the pixel driving circuit 140including the driving transistor Tr1 is formed on the substrate 11.After that, the planarizing insulating film 12 is formed by, forexample, coating the whole area with a photosensitive resin. Then, theplanarizing insulating film 12 is patterned into a given shape byproviding exposure and development. In addition, the connection hole 12Ais formed, and the resultant is fired.

Next, as shown in FIG. 7 as well, the first electrode 13 made of theforegoing material is formed by, for example, sputtering method, andthen is formed into a given shape by, for example, etching. Further, theforegoing auxiliary electrode 14 is formed by, for example, sputteringmethod, and then is formed into a given shape by, for example, etching.The first electrode 13 and the auxiliary electrode 14 may be formed intoa film and formed into a given shape by etching in the same step.Further, the auxiliary electrode 14 may be made of a material differentfrom that of the first electrode 13, formed into a film and formed intoa given shape by etching in a different step.

Subsequently, as shown in FIG. 7 as well, the base 15A of the projectionstructure 15 made of the foregoing material is formed by, for example,photolithography method. Then, the opening corresponding to the lightemitting region of the first electrode 13 and the auxiliary electrode 14is provided.

After that, as shown in FIG. 7 as well, for example, the secondphotolithography is performed, and thereby the rib 15B made of amaterial similar to that of the base 15A is formed on the base 15A inthe planar shape as shown in FIG. 3, FIG. 5, or FIG. 6. Thereby, theprojection structure 15 having the two-stage structure composed of thebase 15A and the rib 15B is formed.

After the projection structure 15 is formed, as shown in FIG. 7 as well,the organic layer 16 covering the first electrode 13 and the auxiliaryelectrode 14 is formed by a general film-forming method such asevaporation method, CVD (Chemical Vapor Deposition) method, printmethod, inkjet method, and transfer method. The organic layer 16 doesnot necessarily cover the whole area over the substrate 11, but may bepattern-formed for every respective organic light emitting devices 10R,10G, and 10B. However, the organic layer 16 should cover the top face ofthe first electrode 13 totally. Thus, even if the organic layer 16 ispattern-formed, the organic layer 16 is extended to the projectionstructure 15 and the auxiliary electrode 14. Thereby, a device substrate10 in which the first electrode 13, the auxiliary electrode 14, theprojection structure 15, and the organic layer 16 are formed over thesubstrate 11 is formed.

After the device substrate 10 is formed, the portion of the organiclayer 16 formed on the auxiliary electrode 14 is selectively removed,and thereby the auxiliary electrode 14 is exposed.

That is, first, as shown in FIG. 8A, the device substrate 10 and thecover substrate 61 are introduced into a chamber 50, and inside of thechamber 50 is maintained in the vacuum atmosphere. After that, in thevacuum atmosphere, the device substrate 10 is laminated over the coversubstrate 61 with the projection structure 15 in between, and alaminated structure 62 is formed. At this time, the projection structure15 becomes a spacer between the device substrate 10 and the coversubstrate 61. Thus, even in the state that the device substrate 10 andthe cover substrate 61 are laminated, the space S is generated betweenthe device substrate 10 and the cover substrate 61.

The vacuum atmosphere is in a state of reduced pressure such as 10⁻¹ Paor less. The vacuum atmosphere also includes a state of reduced pressuresuch as reduced pressure nitrogen atmosphere and reduced pressure dryair atmosphere. In FIG. 8A to FIG. 11, FIG. 13, and FIG. 14, the vacuumatmosphere region is shown as a shaded region. The cover substrate 61 ismade of, for example, a translucent material such as glass and plastic.The cover substrate 61 may be made of a plastic film as long as theplastic film has a rigidity with which space is secured between thecover substrate 61 and the device substrate 10 when the inside of thevacuum chamber 50 is maintained in the vacuum atmosphere.

After the laminated structure 62 is formed, the laminated structure 62is taken out into the air in a state that the space S between the devicesubstrate 10 and the cover substrate 61 is maintained in the vacuumatmosphere. It is not necessary to maintain the entire space S betweenthe device substrate 10 and the cover substrate 61 in the vacuumatmosphere. It is enough that at least the space S that is locatedbetween the cover substrate 61 and the portion of the organic layer 16formed on the auxiliary electrode 14 in the display region 110 ismaintained in the vacuum atmosphere.

In the case where the space S is not communicated with outside of thelaminated structure 62 in the state that the device substrate 10 islaminated over the cover substrate 61, the vacuum atmosphere in thespace S is maintained even after the inside of the chamber 50 isreturned to the state at normal pressures. Thus, the laminated structure62 may be taken out of the chamber 50. Though not shown, the state thatthe space S is not communicated with outside of the laminated structure62 is, for example, a case in which the rib 15B surrounds the outercircumference of the display region 110 with no gap. In addition, such astate may be a case in which as shown in FIG. 6, the rib 15B issequentially provided along the four sides of the first electrode 13,and the rib 15B surrounds at least the space S that is located betweenthe cover substrate 61 and the portion of the organic layer 16 formed onthe auxiliary electrode 14 in the display region 110.

Meanwhile, when the space S is communicated with outside of thelaminated structure 62 in the state that the device substrate 10 islaminated over the cover substrate 61, the laminated structure 62 istaken outside of the chamber 50 by using a jig 70 shown in FIG. 9A. Thecase that the space S is communicated with outside of the laminatedstructure 62 is, for example, as shown in FIG. 3 or FIG. 5, a case thatthe respective ribs 15B are independently formed and a gap exists in theouter circumference of the display region 110.

The jig 70 has a body 71 and a cover 72 made of, for example, stainlesssteel. The bottom face of the body 71 has a size capable of containingthe laminated structure 62 kept in a horizontal position. The height ofthe side face of the body 71 is almost equal to the thickness of thelaminated structure 62. The top face of the body 71 is opened to takeout and put in the laminated structure 62. The cover 72 is attached tothe upper end of the side face of the body 71. An airtight seal portion73 is provided between the body 71 and the cover 72. The cover 72 isformed in a state of a frame having an opening 72A smaller than thelaminated structure 62. An airtight seal portion 74 is provided betweenthe cover 72 and the laminated structure 62.

The jig 70 is introduced into the chamber 50, and the laminatedstructure 62 is sandwiched and held between the body 71 and the cover 72in the state that the inside of the chamber 50 is maintained in thevacuum atmosphere. Thereby, a gap between the body 71 and the cover 72is hermetically sealed by the airtight seal portion 73, a gap betweenthe cover 72 and the laminated structure 62 is hermetically sealed bythe airtight seal portion 74, and thereby inside of the jig 70 becomes astate that the vacuum atmosphere is maintained. Therefore, the vacuumatmosphere in the space S between the device substrate 10 and the coversubstrate 61 is maintained even after the inside of the chamber 50 isreturned to the state at normal pressures. Thus, the laminated structure62 sandwiched and held by the jig 70 may be taken out of the chamber 50.

After the laminated structure 62 is taken out of the chamber 50, asshown in FIG. 8B or FIG. 9B, a laser irradiation device 63 is arrangedon the cover substrate 61 side, and infrared band laser light LB havinga wavelength of 800 nm is emitted by, for example, a semiconductor CW(Continuous Wave) laser from, for example, the cover substrate 61 sideto the laminated structure 62. Since the space S between the devicesubstrate 10 and the cover substrate 61 is maintained in the vacuumatmosphere, even if the laser light LB is emitted to the laminatedstructure 62 taken out into the air, the laser light LB is emitted inthe vacuum atmosphere to the portion of the organic layer 16 formed onthe auxiliary electrode 14.

By irradiating the laser light LB in the vacuum atmosphere to theportion of the organic layer 16 formed on the auxiliary electrode 14,such a portion of the organic layer 16 formed on the auxiliary electrode14 may be removed with the use of energy lower than that in the casethat such a portion is removed in the air, and removal residue may beprevented. Further, thermal damage to the auxiliary electrode 14 and theadjacent organic light emitting devices 10R, 10G, and 10B due toirradiation of the laser light LB may be decreased.

Further, since the laser light LB is emitted to the laminated structure62 in the air, compared to the case that laser is emitted through theglass window of the chamber in the past, the distance between the laserirradiation device 63 and the device substrate 10 may be relativelyshort, and the laser light LB having stable light condensingcharacteristics may be emitted. In addition, the equipment forirradiating the laser light is simplified, leading to cost reduction andcapability of realizing a large substrate.

As described above, as shown in FIGS. 10A and 10B, the portion of theorganic layer 16 formed on the auxiliary electrode 14 is sublimed,adhered again to the cover substrate 61, and then removed. Then, thecover substrate 61 is collected. Thereby, the material of the removedorganic layer 16 is prevented from being adhered again to the devicesubstrate 10, and the device is prevented from being contaminated. Inthe result, a high yield is realized.

As a method of irradiating the laser light LB, when the laserirradiation device 63 has a precise alignment mechanism, the laser lightLB is selectively emitted to part or all of the auxiliary electrode 14.In this case, to secure the removal work, the width of the auxiliaryelectrode 14 may be formed large, considering the width of the laserlight LB and the irradiation precision of the laser light LB.

Meanwhile, in the case where the laser irradiation device 63 does nothave a precise alignment mechanism, as shown in FIG. 11, a shield film61A having an opening 61B corresponding to the region to which the laserlight LB is emitted is previously formed in the cover substrate 61. Whenthe laminated structure 62 is formed, it is preferable that the opening61B of the shield film 61A is precisely aligned with the auxiliaryelectrode 14 on the device substrate 10, and the laser light LB isemitted with the use of the cover substrate 61 as a mask. Thereby, thelaser light LB is not necessarily emitted precisely, and thus, forexample, the laser light LB may be emitted at a time. The shield film61A is, for example, 100 nm or more thick, and is made of a simplesubstance or an alloy of metal elements such as aluminum (Al), chromium(Cr), titanium (Ti), nickel (Ni), and molybdenum (Mo). The opening 61Bis provided by photolithography step or the like.

After the portion of the organic layer 16 formed on the auxiliaryelectrode 14 is removed, the laminated structure 62 is conveyed to thechamber 50 again. After the inside of the chamber 50 is maintained inthe vacuum atmosphere, the cover 72 is separated. Then, as shown in FIG.12A, the cover substrate 61 is separated from the device substrate 10.Though the step of separating the device substrate 10 from the coversubstrate 61 may be performed in the air as well, such a step isdesirably performed in the vacuum atmosphere to retain the devicecharacteristics.

After the device substrate 10 is separated from the cover substrate 61,as shown in FIG. 12B, the second electrode 17 is formed on the organiclayer 16 and the auxiliary electrode 14 by, for example, evaporationmethod, sputtering method, or CVD method. Thereby, the exposed portionof the auxiliary electrode 14 is electrically connected to the secondelectrode 17. After that, according to need, the protective film made ofthe foregoing material is formed on the second electrode 17 by, forexample, evaporation method, sputtering method, or CVD method. Thesealing substrate is bonded to the protective film with the adhesivelayer in between. Consequently, the display unit shown in FIG. 1 iscompleted.

In the display unit, a scanning signal is supplied from the scanningline driving circuit 130 to each pixel through the gate electrode of thewriting transistor Tr2. An image signal from the signal line drivingcircuit 120 is retained in the retention capacity Cs through the writingtransistor Tr2. That is, the driving transistor Tr1 is on/off-controlledaccording to the signal retained in the retention capacity Cs. Thereby,driving current Id is injected into the respective organic lightemitting devices 10R, 10G, and 10B. In the result, electron-holerecombination occurs, and thereby light is emitted. The light isextracted through the second electrode 17, the protective film, and thesealing substrate. In this embodiment, the portion of the organic layer16 formed on the auxiliary electrode 14 is removed by laser irradiationin the vacuum atmosphere. Thus, the removal residue is low, and theelectrical connection between the auxiliary electrode 14 and the secondelectrode 17 is favorable. Therefore, a current supplied from the powersource (not shown) is flown to the respective organic light emittingdevices 10R, 10G, and 10B through the auxiliary electrode 14 withoutgenerating a large difference in voltage drop. In the result, an imagewith uniform luminance is displayed over the entire screen.

As above, in this embodiment, in the step of selectively removing theportion of the organic layer 16 formed on the auxiliary electrode 14,the laminated structure 62 is formed by placing the cover substrate 61over the device substrate 10 with the protrusion structure 15 in betweenin the vacuum atmosphere, the laminated structure 62 is taken out intothe air in the state that the space S between the device substrate 10and the cover substrate 61 is maintained in the vacuum atmosphere, andthen the laser light LB is emitted to the laminated structure 62.Therefore, the portion of the organic layer 16 formed on the auxiliaryelectrode 14 may be removed by laser irradiation in the vacuumatmosphere.

In the foregoing embodiment, the description has been given of the casethat the projection structure 15 has the two-stage structure composed ofthe base 15A and the rib 15B. However, the projection structure 15 doesnot necessarily have the rib 15B. As shown in FIG. 13, the projectionstructure 15 may be composed of only the base 15A. Thereby, theprojection structure 15 may be formed by one time photolithography step,and the manufacturing step is further simplified. In this case, theheight H of the projection structure 15 is preferably, for example, 2 μmor more from the front face of the first electrode and the front face ofthe auxiliary electrode 14.

Further, in the foregoing embodiment, the description has been given ofthe case that the first electrode 13 and the auxiliary electrode 14 areformed on the planarizing insulating film 12. However, as shown in FIG.14, as the pixel driving circuit 140 including the driving transistorTr1, the auxiliary electrode 14 may be formed on the substrate 11, andmay be connected to the second electrode 17 through a connection hole12B provided in the planarizing insulating film 12.

MODULE AND APPLICATION EXAMPLES

A description will be given of application examples of the display unitdescribed in the foregoing embodiment. The display unit of the foregoingembodiment is applicable to a display unit of an electronic device inany field for displaying an image signal inputted from outside or animage signal generated inside as an image or a picture, such as atelevision device, a digital camera, a notebook personal computer, aportable terminal device such as a mobile phone, and a video camera.

Module

The display unit of the foregoing embodiment is incorporated in variouselectronic devices such as after-mentioned first to fifth applicationexamples as a module as shown in FIG. 15, for example. In the module,for example, a region 210 exposed from a sealing substrate 30 and anadhesive layer 20 is provided on a side of the substrate 11, and anexternal connection terminal (not shown) is formed in the exposed region210 by extending the wirings of the signal line driving circuit 120 andthe scanning line driving circuit 130. The external connection terminalmay be provided with a Flexible Printed Circuit (FPC) 220 for inputtingand outputting a signal.

First Application Example

FIG. 16 is an appearance of a television device to which the displayunit of the foregoing embodiment is applied. The television device has,for example, an image display screen section 300 including a front panel310 and a filter glass 320. The image display screen section 300 iscomposed of the display unit according to the foregoing embodiment.

Second Application Example

FIGS. 17A and 17B are an appearance of a digital camera to which thedisplay unit of the foregoing embodiment is applied. The digital camerahas, for example, a light emitting section for a flash 410, a displaysection 420, a menu switch 430, and a shutter button 440. The displaysection 420 is composed of the display unit according to the foregoingembodiment.

Third Application Example

FIG. 18 is an appearance of a notebook personal computer to which thedisplay unit of the foregoing embodiment is applied. The notebookpersonal computer has, for example, a main body 510, a keyboard 520 foroperation of inputting characters and the like, and a display section530 for displaying an image. The display section 530 is composed of thedisplay unit according to the foregoing embodiment.

Fourth Application Example

FIG. 19 is an appearance of a video camera to which the display unit ofthe foregoing embodiment is applied. The video camera has, for example,a main body 610, a lens for shooting an object 620 provided on the frontside face of the main body 610, a start/stop switch in shooting 630, anda display section 640. The display section 640 is composed of thedisplay unit according to the foregoing embodiment.

Fifth Application Example

FIGS. 20A to 20G are an appearance of a mobile phone to which thedisplay unit of the foregoing embodiment is applied. In the mobilephone, for example, an upper package 710 and a lower package 720 arejointed by a joint section (hinge section) 730. The mobile phone has adisplay 740, a sub-display 750, a picture light 760, and a camera 770.The display 740 or the sub-display 750 is composed of the display unitaccording to the foregoing embodiment.

While the invention has been described with reference to the embodiment,the invention is not limited to the foregoing embodiment, and variousmodifications may be made. For example, the material, the thickness, thefilm-forming method, the film-forming conditions, and laser lightirradiation conditions and the like of each layer are not limited tothose described in the foregoing embodiment, but other material, otherthickness, other film-forming method, other film-forming conditions, andother irradiation conditions may be adopted. For example, the firstelectrode 13 may be made of ITO or IZO (indium zinc composite oxide).Further, the first electrode 13 may have a dielectric multilayer film.

In addition, for example, in the foregoing embodiment, the descriptionhas been given of the case in which the first electrode 13, the organiclayer 16, and the second electrode 17 are layered in this order from thesubstrate 11 side over the substrate 11, and the light is extracted fromthe sealing substrate side. However, it is possible that the laminationorder is reversed. That is, it is possible that the second electrode 17,the organic layer 16, and the first electrode 13 are sequentiallylayered from the substrate 11 side over the substrate 11, and the lightis extracted from the substrate 11 side.

Furthermore, for example, in the foregoing embodiment, the descriptionhas been given of the case in which the first electrode 13 is used as ananode and the second electrode 17 is used as a cathode. However, it ispossible that the anode and the cathode are reversed. That is, it ispossible that the first electrode 13 is used as a cathode and the secondelectrode 17 is used as an anode. Further, it is possible that the firstelectrode 13 is used as a cathode and the second electrode 17 is used asan anode, and the second electrode 17, the organic layer 16, and thefirst electrode 13 are sequentially layered from the substrate 11 sideover the substrate 11, and the light is extracted from the substrate 11side.

In addition, in the foregoing embodiment, the description has beenspecifically given of the structure of the organic light emittingdevices 10R, 10G, and 10B. However, it is not necessary to provide alllayers, and other layer may be further provided. For example, an holeinjection thin film layer made of chromium oxide (III) (Cr₂O₃), ITO(Indium-Tin Oxide: oxide mixed film of Indium (In) and tin (Sn)) or thelike may be provided between the first electrode 13 and the organiclayer 16.

Furthermore, in the foregoing embodiment, the description has been givenof the case in which the second electrode 17 is made of the translucentelectrode, and the light generated in the light emitting layer isextracted from the second electrode 17 side. However, the generatedlight may be extracted from the first electrode 13 side. In this case,it is desirable that the second electrode 17 has reflectance as high aspossible to improve the light emitting efficiency.

In addition, in the foregoing embodiment, the description has been givenof the active matrix display unit. However, the invention is alsoapplicable to a passive matrix display unit. Furthermore, the structureof the pixel driving circuit for the active matrix driving is notlimited to the structure described in the foregoing respectiveembodiment. If necessary, a capacity device or a transistor may beadded. In this case, according to the change of the pixel drivingcircuit, a necessary driving circuit may be added in addition to theforegoing signal line driving circuit 120 and the scanning line drivingcircuit 130.

It should be understood by those skilled in the art that variousmodifications, combination, sub-combinations and alternations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A method of manufacturing a display unit having a plurality oforganic light emitting devices on a substrate, the method comprising thesteps of: (a) forming a device substrate by forming a plurality of firstelectrodes, an auxiliary electrode in a region between the plurality offirst electrodes, a projection structure made of an insulating materialin a region between the plurality of first electrodes and the auxiliaryelectrode, and an organic layer covering the plurality of firstelectrodes and the auxiliary electrode over the substrate; (b)selectively removing a portion of the organic layer formed on theauxiliary electrode; and (c) forming a second electrode on the organiclayer and the auxiliary electrode, wherein, the step of selectivelyremoving the portion of the organic layer formed on the auxiliaryelectrode includes the steps of: (b1) first forming, prior to a removalof the portion of the organic layer formed on the auxiliary electrode, alaminated structure that includes a cover substrate and the devicesubstrate by placing the cover substrate over the device substrate withthe projection structure in between in the vacuum atmosphere, (b2) afterthe step of forming the laminated structure, taking out the laminatedstructure into the air in a state such that at least a space between thecover substrate and the portion of the organic layer formed on theauxiliary electrode is maintained in the vacuum atmosphere prior to theremoval of the portion of the organic layer formed on the auxiliaryelectrode, (b3) thereafter, while at least the space between the coversubstrate and the portion of the organic layer formed on the auxiliaryelectrode is being maintained in the vacuum atmosphere, irradiatinglaser light to the laminated structure on a cover substrate side so asto remove the portion of the organic layer formed on the auxiliaryelectrode, the auxiliary electrode being under the cover substrate whilethe laser light is being irradiated to remove the portion of the organiclayer formed on the auxiliary electrode in the vacuum atmosphere, and(b4) separating the cover substrate and the device substrate after theportion of the organic layer formed on the auxiliary electrode isremoved with the laser light.
 2. The method of manufacturing a displayunit according to claim 1, wherein the projection structure comprises: abase provided in the region between the plurality of first electrodesand the auxiliary electrode; and a rib provided on part of a top face ofthe base.
 3. The method of manufacturing a display unit according toclaim 1, wherein the cover substrate includes a shielding film having anopening corresponding to a region to which the laser light is emitted.